While the Antarctic Plate is primarily considered oceanic, Mount Erebus is a stratovolcano that formed at a divergent plate boundary. This means that the Antarctic Plate is slowly pulling apart at this location, allowing magma from the mantle to rise and erupt, forming the volcano.

It's important to note that even though Mount Erebus is on the Antarctic Plate, it's not directly on the plate boundary. It sits within the West Antarctic Rift System, which is a zone of intense volcanic activity caused by the plate pulling apart.